A modular computer chassis comprises a main chassis to which a motherboard is attached and a subchassis attachable to the main chassis. The subchassis is capable of having at least one computer component attached thereto such that the computer component is electrically connected to the motherboard. The computer component is thus separable from the main chassis by removing the subchassis from the main chassis. The subchassis contains those computer components subject to mechanical wear and most often requiring replacement, i.e. the power supply and disk drives. The subchassis is mechanically connected to the main chassis by using slots and tabs such that when the cover is in place upon the computer, then the subchassis is secured therein. The subchassis and the computer components disposed thereon thus form a module which is conveniently removable and replaceable such that those computer components most frequently requiring service can be quickly removed and replaced by a person unskilled in computer repair.